Neutron scattering study on Zn-doped YBa2CU3O6+y system

Neutron scattering studies on a c-axis polarized B-2u phonon and magnetic e xcitations of the YBa2Cu3-xZnxO6+y system were carried out. For YBa2Cu2.9Zn 0.1O6.75, anomalies of the B-2u mode related to the spin (pseudo) gap forma tion are insensitive to the Zn-doping. In the magnetic excitation spectra o f YBa2Cu3O6+y samples which are close to the metal-insulator phase boundary , a gap-like structure can be seen at high temperatures, while at low tempe ratures the low energy spectral weights increase and the gap-like structure disappears. This suggests that the itinerant nature has an important role in the spin gap formation. (C) 1999 Elsevier Science Ltd. All rights reserv ed.